Jeremy Vine mistakenly believed the brother of a caller on his BBC Radio 2 show got his foreskin caught in a lift.
During a discussion about consent for circumcision on Tuesday's edition, listener Milly from East Sussex explained why she made the decision to have her two sons circumcised.
"In 1969, I asked for my son to be done because of what I saw my brother went through when I was younger. He had his foreskin caught in a zip."
"In a lift?" Jeremy queried.
"In a zip," Milly repeated.
The broadcaster apologised and Milly went on to explain that her brother's experience was the reason she decided to have her first-born circumcised.
Jeremy's gaffe sparked a good deal of mirth on social media.
"Crying laughing at Jeremy Vine mishearing a caller," one person tweeted.
The BBC presenter and Strictly Come Dancing star posted on Twitter: "She said zip and I misheard."
Thursday's edition of Jeremy's topical show included a segment devoted to Forces' Sweetheart Dame Vera Lynn.
The much-loved singer, 99, has been recognised by the Soldiering On Awards for her outstanding contribution to the morale of servicemen and women during the Second World War, and their families back home.
Jeremy presented her with the award and said meeting her was "one of the most magical afternoons" of his career.
"I found it very emotional," he said. "I walked into her living room and there she was, lively and with time for me and the team. She talked about the war years, and those that followed, with crystal clarity."
He added: "Those eyes fix you - they're like steel! And she wanted me to stay and look through her photo albums. I couldn't believe it - I am being shown photos of Vera Lynn by Vera Lynn, I thought. One of the most magical afternoons of my career."